Sheet driving and aligning mechanism



March 30, 1965 c. A. ALBOSTA 3,175,824

SHEET DRIVING AND ALIGNING MECHANISM Filed Sept. 7, 1962 3 Sheets-Sheet 1 ul,,llllll,laralinvi -k lll'lIIIIIIIIIIII'IIIIIII,

INVENTOR CHESTER A. ALBOSTA ATTORNEY March 30, 1965 c. A. ALBOSTA 3,175,824

SHEET DRIVING AND ALIGNING MECHANISM Filed Sept. 7, 1962 3 Sheets-Sheet 2 March 30, 1965 I c. A. ALBOSTA 3,175,824

SHEET DRIVING AND ALIGNING MECHANISM Filed Sept. 7, 1962 3 Sheets-Sheet 3 v} WITH BEVELED COCKING ANGLE e (DEGREES) c IMPROVED W ARRANGEMENT c PRIOR ART tration with said edge.

employing a mechanism of this type.

nited States This invention relates to sheet driving and aligning mechanisms, and more particularly to an improved mechanism embodying means for driving sheets at a substantially constant forward velocity and translationally at an oblique angle during their alignment laterally against a registration edge.

It is now common practice to imprint, on bank checks, magnetic ink code indicia to identify the account number and other numerically coded information. This indicia is imprinted at a prescribed distance from the lower longitudinal edge of the check. So that the read means will scan the proper area of the check, the checks must be aligned against the reference edge before they pass the read means.

In aligning apparatus currently being used, it is customary to employ a caster wheel with a surface of high friction material that is driven by a drive roll having a surface of low friction material. The caster wheel is spring-biased to swivel through a preselected cocking angle toward a registration edge against which the checks are to be aligned. When no check is in the bite between the caster wheel and drive roll, the roll drives the caster wheel such that it is skewed only slightly toward the registration edge by the action of the bias spring. As soon as a check enters the bite, the forces on the check become unbalanced. The caster wheel promptly swivels through said cocking angle and remains cocked until it has moved the check obliquely toward and into regis- While the caster wheel is cocked, its velocity is reduced because of the skewed drive. The forward component of velocity of the caster wheel and hence of the check is reduced to a value equal to their normal terminal velocity multiplied by the square of the cosine of the cocking angle. This reduction in forward velocity of the checks during aligning undesirably tends to decrease the spacing between the check being aligned and the succeeding check and hence causes a risk of having insufficient time between checks for computing and selection and results in a rejected document for spacing reasons in a machine such as a bank-check reader/ sorter, Since checks are of random varying widths and lengths, the time required to align a check and also the ratio of the aligning time to the driving time after alignment will vary. Hence, the variable gaps created as a result of aligning cannot reliably be increased merely by driving sheets faster after alignment.

Moreover, arrangements heretofore proposed employ a single caster wheel or else several caster wheels that are serially arranged along the transport path. Because the caster wheels must be of narrow width, they make substantially only point contact with the sheet. When the check is under control of a singular caster, the checks are free to fishtail. Because of this possibility of fishtailing, machines must be designed to permit sufficient check travel along the transport path to assure accurate aligning.

It is therefore among the objects of this invention to provide an improved sheet driving and aligning mechanism, wherein:

(a) Alignment time is reduced, permitting alignment to be completed with shorter travel along the transport path.

(b) Fishtailing is eliminated.

(c) The spacing between sheets after alignment is not affected by the amount of initial misalignment of the respective sheets.

(d) The reliability of a machine is increased because it is no longer adversely affected by the degree of initial misalignment of the sheets causing document spacing rejects.

(e) Sheets of varying random lengths, widths and thicknesses can be aligned against a stationary or moving registration edge.

(1) As the caster wheel wears, each caster wheel will be maintained biased down against the corresponding drive roll with a constant preselected normal force; and upward movement of the caster wheel is clamped to limit bounce and vibration.

According to these objects, the improved sheet driving and aligning mechanism comprises a pair of caster ele- 'tfilliS, each resiliently biased through a preselected cocking angle and toward a registration edge against which sheets, such as checks, are to be aligned. Each caster element cooperates with a frustro-conical or beveled surface of a respective driven roll to provide two bites which are spaced transversely along a line generally perpendicular to the registration edge. Thus, after a sheet enters these transversely spaced bites, the sheet will always be pinched and driven at two spaced points. This will assure that the sheet will be driven translationally at an oblique angle toward the registration edge for rapid alignment thereagainst without fishtailing.

Each caster wheel is carried by a caster arm that is movable in an are relative to a vertical spindle. Hence, as the cocking angle increases, each caster wheel will ride on progressively increased diametral portions of the corresponding beveled drive roll, thus increasing the actual peripheral speed of the caster wheel and hence of the check. However, the taper of the beveled surface and the effective length of the rockable caster arm are so selected that the actual or resultant velocity of the check will vary as necessary to maintain the forward component of velocity of the caster wheel and-hence of the check substantially constant at a preselected value. This value corresponds to the total peripheral velocity of the check in the forward direction after alignment. Hence, during alignment, the forward velocity of the check is substantially equal to the total velocity of the check after alignment.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings, wherein:

FIG. 1 is a side elevational view, partly in section, of a sheet driving and aligning mechanism embodying the invention;

FIG. 2 is a section view, partly broken away, taken along line 2--2 of FIG. 1;

FIG. 3 is a front view, looking in the direction of arrow 3 in FIG. 1;

FIG. 4 is an enlarged view, partly in section, of the caster wheel and its support structure shown in outline in FIG. 3;

FIG. 5 is a sectional view taken along the line 5--5 of FIG. 4;

FIG. 6a is a curve showing how the forward and lateral components of caster wheel and sheet velocity vary with variation in the cooking angle of the caster wheels when driven by a frustro-conical driven roll and by an unbeveled cylindrical driven roll, whereas FIG. 6b is a diagram graphically defining the various elements depicted on said curve;

FIG. 7 diagrammatically shows the aligning action ob- 3 tained when a single caster wheel is used as proposed in the prior art; and

FIG. 8 shows the improved aligning action obtained by use of two transversely spaced caster wheels according to a feature of the present invention.

Description As shown in FIGS. 1-3, the sheet driving and aligning mechanism embodying the invention comprises a pair of transversely spaced caster wheels 10, each having a peripheral surface that is formed of high friction material and rides on a beveled low friction surface 11 of a frustroconical driven roll 12. As illustrated in FIG. 1, each roll 12 is driven by a respective shaft 13. These shafts 13 are parallel and so disposed that the beveled surfaces 11 and caster wheels will provide two transversely spaced bites lying substantially within a common plane. Above and below this plane are closely spaced upper and lower guide plates 14, 15. Suitable openings are provided in these plates to permit the respective caster wheels 15! to contact the corresponding surfaces 11.

As illustrated, each drive shaft 13 is suitably journaled in a bearing provided in a corresponding fixed bracket 16. Also, each shaft 13 is preferably separately driven through a respective belt 17 and associated pulley.

Each caster wheel it) is rotatably mounted on a shaft 18 that is carried near one end of a laterally offset caster support arm 19. Near its respective other end, each arm 19 carries a spindle 20 (FIG. 5) that projects upwardly into bearings 21 that are housed in a bore or socket 22 in a housing 23. A nut 24 (FIG. 5) is screw-threaded onto the upper end of each spindle to prevent axial movement of the spindle and caster wheel relative to the housing 23, but permit rotation of the spindle and hence arcuate movement of the caster wheel relative to the spindle. A pair of helical springs 25 are provided, each anchored at their respective ends to the corresponding housing 23 and to a lug forming part of the arm 19. Each spring 25 biases the corresponding arm 19 and hence caster wheel 10 clockwise, as viewed in FIG. 2, through a preselected cocking angle 0 to the cocked position indicated by broken lines in FIG. 2. This cocking angle is defined by lateral contact of a stop lug 26 (FIG. 5) on each arm 19 with a corresponding stop surface (not shown) provided by each housing 23. Each stop lug 26 is adapted to contact a respective stop surface 27 provided by each housing to define a straight-ahead position of the caster wheel 16. This assures that the caster wheel cannot swing in a negative direction, thereby positively preventing the check from rebounding off the aligning edge.

Referring now to FIGS. 4 and 5, a pair of constant force-type helical springs 30 are provided. Each spring 30 is connected at one end to an ear on the corresponding housing 23 and at the other end to a corresponding stationary member 31. As illustrated, this spring is of the type known as a Flexator spring, which is made and sold by Hunter Spring Company. Each spring 30 acts to bias the corresponding caster wheel Ill with a constant normal force toward contact with the beveled surface 11 of the corresponding driven roll 12. The biasing action of each spring 30 is constrained to act in a substantially mum acceleration and aligning. This preselected value 'of normal force should then be maintained constant.

This requires not only a constant force-type spring. such as the spring 30, but requires a spring rate near zero since wear of the caster wheel must not alfect normal tempt to move up.

force. The natural frequency of the aligner assemblage 10, 23, in the vertical direction varies directly with the square root of the spring rate. Hence, a spring rate of zero means Zero natural frequency. But, with high speed operation, severe vibration would then occur when a check entered under the caster wheels 10. It is therefore necessary, for high speed operation, to employ a high natural frequency and hence a high natural spring rate, in order to limit bounce and vibration.

Accordingly, a damping control mechanism 35 is associated with each caster wheel 10 to insure that a constant downward or normal force will be exerted on each caster wheel throughout the useful life of the wheel, and upward movement of the caster wheel will be damped effectively.

Each mechanism 35 is preferably disposed within a hollow cover or casing 36 (FIGS. 4, 5) that is secured, as by screws 37, to an arm 33 formed integrally with the corresponding stationary member 31. A'vertically disposed cylindrical locking rod 39 extends downwardly through a guide bore 463 through each fixed arm 38. Each rod 39 is held stationary, such as by a set screw .1. Teach rod 39 projects concentrically downward through a correspending retaining cap 42 and into a bore provided in a corresponding friction locking member 43. Extending concentrically downward from the upper end of each member 43 is a tapered counter bore 44 with a predetermined taper angle. The exterior of each cylindrical rod 39 and the wall of each corresponding tapered counter bore 44 define respective annular conical chambers, each containing a ring of steel locking balls 45. Each retaining cap 42 overlies the upper end of the corresponding member 43 and encloses the large end of the ball-receiving chamber. A helical spring 46 encircles each rod 39 and is interposed between the corresponding arm 38 and the upper end of the associated retaining cap 42. This spring exerts a very light downward bias force on the cap 42 to maintain the balls 45 within the corresponding chamber. A damping spring 47 encircles the lower end of each rod 39 and is interposed between the lower end of each member 43 and a spring seat formed in the upper end of the corresponding housing 23. Each damping spring 47 has a high natural frequency and hence a high spring rate, and is normally uncompressed.

With the damping mechanisms 35 just described, the high rate of damping springs 47 will extort a downward force on the corresponding housings 23 and hence on the associated caster wheels 10 only when said housings at- In other words, the constant forcetype springs 39 act through the respective housings 2.3 to exert a constant downward or normal force; however, movement of the caster wheels and housings in the upward direction is permitted, but is effectively damped by the high rate damping springs 47. As the caster wheels 10 wean-the housings 23 will move correspondingly downward a slight degree. This will permit the light bias springs 46 to shift the retaining caps 42 and hence the members 43 downward a corresponding extent without compressing the damping springs 47; but rods 39 will be held stationary by screws 41. If a caster wheel ft) is replaced, the member 43 can be elevated to its initial starting position by concurrently rotating it and pushing it upward. Upward movement of each member 43 relative to the stationary rod 39 is possible because of the difference between the static and kinetic coefficients of friction; i.e., the balls 45 have a lower coefiicient of friction when rolling than when at rest.

As illustrated, the sheet driving and aligning mechanism is employed to align checks, such as St), against a moving registration edge 51. This moving registration edge is defined by a radial shoulder of a flanged portion or rim of an aligning drum 52. Drum '52 is rotatable by a shaft 53 that is journaled in a back plate 5% and driven by suitable means (not shown). However, while it is desirable, it is not essential for purposes of the present invention that the registration edge be defined by a moving member.

Operation Assume initially that driven rolls 12 are being driven at equal velocities by their respective drive belts 17; that a check 50 is being pinched at two transversely spaced points corresponding to the bites defined between each caster wheel and its respective tapered drive surface 11; and that one longitudinal edge of the check 50 has already been aligned laterally against the registration edge 51, which edge, it will be noted from the drawings, extends in a direction generally perpendicular to a line running through said transversely spaced points.

Under the assumed conditions, the various components will assume the respective positions in which they are shown in FIGS. 1 to 5 of the drawings. It is to be noted that, because of the driving action of the corresponding rolls 12, each cocking bias spring 25 will be stretched somewhat to an abnormal position, as shown by solid lines in FIGS. 1 and 2. When in this position, each caster wheel rotates in a plane substantially parallel to the registration edge. However, when in a normal position, shown by dotted lines in FIG. 2, each caster wheel will be disposed at the preselected oblique angle 6 to the registration edge 51.

After the aligned check 50 leaves the bites of the caster wheels 10 and the rolls 12, the next check 50a (FIG. 2)

will enter said bites. As this time, the right-hand longi- 'tudinal edge of check 50a will be spaced from the registration edge 51 as shown in FIG. 2.

Since the bites of wheels 10 and rolls 12 lie on a line which is generally perpendicular to the registration edge 51, the leading edge of the check 50a will (unless skewed) enter both bites substantially simultaneously. Thus, the check will be pinched and driven at two transversely spaced points simultaneously, as shown in FIG. 8a. As soon as the check 50a moves between the caster wheels 10 and the drive rolls 12, the rolls will no longer drive the caster wheels and hence will not longer maintain them substantially parallel to the registration edge. Actually, the caster wheels will immediately swived through the prescribed cocking angle 0 due to the bias force exerted by the respective springs 25. In so doing, they will assume the positions shown in dotted lines in FIG. 2 and also shown diagrammatically in FIG. 8b.

As each caster wheel 10 is thus swiveled, or cocked, it will swing in an are relative to the corresponding spindle 20. This will shift the bite or point of contact of each caster wheel 10 with its corresponding roll 12 rightward, as viewed in FIGS. 1 and 2. This, in turn, will cause each caster wheel to contact a larger diameter portion of the beveled drive surface 11 of the corresponding drive roll 12. The increased peripheral velocity of this larger diameter portion will, of course, cause a corresponding increase in the actual or resultant velocity of the particular caster wheel. However, the frustro-conical surface 11 of each drive roll 12 is beveled at an angle which is calculated, for a prescribed length of caster arm 19 and cocking angle 0, to maintain for the caster wheel and hence for the check a forward component of velocity V that is substantially equal to that obtained when the cocking angle is zero and the check is fully aligned.

For example, as shown in FIG. 6a, if the caster wheels assume a selected cocking angle of 20 during alignment, the forward component of velocity V of the check during alignment will be equal to the normal terminal velocity of the check after alignment. V represents the lateral component of velocity of the check obtained during alignment at various cocking angles. Thus, while each caster wheel 10 is cocked, the beveled surface 11 increases the resultant velocity or actual velocity V of the caster wheel 10 to that degree necessary to maintain the forward component of velocity V of the caster wheel and hence of the check substantially constant. By way of comparison, the curves V and V,,' represent the curves obtained when a conventional cylindrical (non-beveled) drive roll is used instead of the beveled or frusto-conical drive rolls herein proposed. It will thus be noted that, with non-beveled drive rolls, the forward component of velocity V,,' of the caster wheels and hence of the check will drop off as soon as the caster wheels are cocked even a slight degree.

As shown in FIG. 8b and c, the check 50a is advanced without fishtailing and translationally at an oblique angle toward the registration edge 51. As soon as the check becomes aligned against edge 51, the springs 25 will be stretched as the caster wheels 10 again are driven in a direction generally parallel to said edge, as shown in FIG. Of course, if the check should be slightly askew as it approaches the position shown in FIG. So, it will not be pinched at the two transversely spaced points at the same instant. In such case, the check may tend to pivot for a split second until the check has moved forward enough to be gripped at the two spaced points. After that, it will be moved translationally without fishtailing toward edge 51.

By way of contrast, when a check is pinched in conventional manner at only one point, the check will tend to fishtail or pivot as shown in FIG. 7, until it finally becomes aligned. This means that a greater distance must be provided along the transport path to reliably accomplish alignment. With applicants arrangement, however, alignment is achieved in a shorter distance without fishtailing, as shown in FIG. 8.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is: 1. Mechanism for aligning sheets and driving them forward along a registration edge, comprising a drive arrangement including caster means and endless drive means providing at least one bite for receiving and driving sheets relative to said edge,

means for cocking the caster means while a sheet is within the bite to cause the caster means to direct such sheet toward said edge, and

means forming part of said arrangement for automatically varying the peripheral speed of the caster means as necessary during driving of each sheet to maintain the forward component of velocity of each sheet substantially constant despite variations in the degree of cocking of the caster means.

2. Mechanism for aligning sheets and driving them forward along a registration edge, comprising a drive arrangement including a plurality of pairs of caster means and corresponding endless means providing a corresponding plurality of sheet-receiving bites arranged substantially in a line generally at right angles to the registration edge,

means for cocking each caster means to substantially the same preselected angle while a sheet is within the bites, to cause all caster means to act cooperatively to direct such sheet obliquely and translationally without fishtailing toward said edge, and said endless drive means automatically varying the peripheral speed of each caster means as necessary to maintain the forward component of velocity of the sheet substantially constant irrespective of the degree of cocking of each such caster means.

3. Mechanism for aligning sheets against and driving them forward along a registration edge, comprising drive means providing a surface wherein points near one lateral edge thereof are driven faster than those near the opposite lateral edge thereof,

a caster coacting with said surface to provide a sheetreceiving bite, and

means for resiliently cocking said caster through a preselected angle,

said surface being so Iconfigur ecl and disposed relative to the caster that, when the caster is cocked, it will ride on a portion of said surface between said lateral edges having a higher linear velocity than the portion ridden on when uncocked so as to maintain the forward component of velocity of the sheet substantially constant.

. 4. Mechanism for aligning sheets against and driving them forward along a registration .edge comprising 5. Mechanism according to claim 4, wherein the coefficient of friction of the beveled surface is less than the coefiicient of friction of the drive-roll-engaging surface of the caster.

6. A sheet driving and aligning mechanism comprising means providing a registration edge,

rotating drive means,

a .pair of caster elements cooperating with said drive means to provide bites which are transversely spaced along a line generally perpendicular to said registration edge, and

means for resiliently cocking each caster element independently at substantially the same predetermined angle oblique to said edge so as to drive said sheets toward said registration edge without 'fishtailing.

7. A mechanism according to claim '6, wherein the registration edge-providing means provides a moving registration edge which moves generally in the direction imparted to the sheets by the driven means, and wherein the driven means tend to drive the sheets in a direction parallel to said registration edge.

8. A mechanism according to claim 6, wherein the rotatably driven means comprises a pair of rolls, one contactable by each caster element, said rolls having beveled drive surfaces so configured that, as the cocking angle ofeach casterelement increases, such element will ride on a progressively increased diameter part of the corresponding roll, said part being so beveled as always to maintain the forward component of velocity of the'sheet substantially constant both during and after alignment.

References Cited by the Examiner UNITED STATES PATENTS 1,291,089 1/19 Novick 27l52 2,181,241 11/39 Klemrn 27l--52 2,190,417 2/40 Davidson 271-52 2,767,982 10/56 Noon 27152 X 2,819,078 1/58 Durand 271-52 X SAMUEL F. COLEMAN, Acting Primary Examiner.

ROBERT A. LEIGHEY, RAPHAEL M. LUPO,

Examiners. 

1. MECHANISM FOR ALIGNING SHEETS AND DRIVING THEM FORWARD ALONG A REGISTRATION EDGE, COMPRISING A DRIVE ARRANGEMENT INCLUDING CASTER MEANS AND ENDLESS DRIVE MEANS PROVIDING AT LEAST ONE BITE FOR RECEIVING AND DRIVING SHEET RELATIVE TO SAID EDGE, MEANS FOR COCKING THE CASTER MEANS WHILE A SHEET IS WITHIN THE BITE TO CAUSE THE CASTER MEANS TO DIRECT SUCH SHEET TOWARD SAID EDGE, AND MEANS FORMING PART OF SAID ARRANGEMENT FOR AUTOMATICALLY VARYING THE PERIPHERAL SPEED OF THE CASTER MEANS AS NECESSARY DURING DRIVING OF EACH SHEET TO MAINTAIN THE FORWARD COMPONENT OF VELOCITY OF EACH SHEET SUBSTANTIALLY CONSTANT DESPITE VARIATIONS IN THE DEGREE OF COCKING OF THE CASTER MEANS. 